Lean Body Mass Calculator
Estimate your lean body mass from height, weight, and sex.
Quick answer
Lean body mass is everything that isn't fat — muscle, bone, organs, and water. It equals total weight minus fat mass (weight × body-fat%). It's useful for setting protein needs and seeing whether weight change is fat or muscle.
Lean body mass (Boer)
56 kg
Body fat implied
20.0%
Fat mass
14 kg
What LBM includes
Lean body mass is everything that isn't fat: muscle, bone, organs, and water. The Boer formula estimates it from height and weight and is the version used clinically for drug dosing. It can't see individual muscularity — very lean or very muscular people will read low.
Why track it
In a diet, the goal is losing fat while holding LBM — adequate protein and resistance training are the levers. Comparing LBM estimates over months (same formula, same conditions) shows whether weight loss is coming from the right place.
Frequently asked questions
- How does the Lean Body Mass Calculator work?
- Lean body mass is everything that isn't fat — muscle, bone, organs, and water. It equals total weight minus fat mass (weight × body-fat%). It's useful for setting protein needs and seeing whether weight change is fat or muscle.
- Is the Lean Body Mass Calculator free to use?
- Yes. The Lean Body Mass Calculator is completely free, runs entirely in your browser, and requires no account or sign-up. Your inputs never leave your device.
Sources & methodology
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